The invention concerns an apparatus for removing broken-out pieces, in particular waste potions, from a sheet of material containing blanks or the like flat portions, as set forth in the classifying portion of the independent claim.
EP 0 446 702 B1 to the present applicant discloses that automatic stamping machines for the production of blanks from sheets of card in the folding box industry have been provided for more than 30 years with breaking-out devices which are preferably arranged in a setting-up table outside the stamping machine. Such a breaking-out station is of particular importance in terms of manufacture as in the event of incorrect use it involves the highest proportion of the total setting-up time and a poorly set breaking-out station results in continual disturbances in the production procedure.
In the breaking-out station the stamped cardboard sheet, after reaching a predetermined detent position, on the breaking-out surface which is usually provided by a breaking-out board or a female die, is freed of the waste by means of breaking-out pins or cutting edges which press from above.
Development in the breaking-out procedures involved firstly entailed the top tool pin which presses downwardly from above and which passes the waste portion through the opening in the breaking-out board. There was then added an additional bottom tool with bottom pins, which are aligned with the top tool pins and which clampingly hold the waste portion. As a breaking-out tool can reliably break out a waste portion only when there is a certain force-locking engagement between the tool and the waste portion, the above-mentioned bottom pins have proven to be an advantageous resistance at the moment when the breaking-out tool or breaking-out member comes to bear against the waste portion.
If there is a wish to avoid using a clamping tool, the breaking-out opening in the breaking-out surface must be smaller at various locations, than the waste portion which is associated therewith, so that the waste portion rests with a relatively high friction, in small surface areas, on the breaking-out surface or female die. When the breaking-out pin comes into contact with the waste portion, the above-mentioned resistance occurs by virtue of the friction which is then produced. When the breaking-out pin and the waste portion pass through the opening, friction occurs at the relatively close walls of the hole, whereby a certain force-locking action is achieved.
DE-A-25 35 452 discloses the so-called DYN-pin, namely a breaking-out pin having a tip or point whose substantially conical side walls are of contours which are concave in cross-section, with a smooth surface. In the breaking-out procedure, that tip bears against the waste portion which, by virtue of being supported on the edges of the opening, opposes the tip with such a level of resistance that the tip can penetrate slightly into the material of the waste portion. That prevents unwanted lateral deflection movement of the waste portion. As it passes through the opening, the waste portion bends, and the stressing force between it and the wall of the opening is intended to afford the DYN-pin sufficient friction for the desired force-locking engagement with the waste portion; that could then possibly make a bottom tool in itself unnecessary, when using the DYN-pin.
As a simplification for breaking-out tools, above-mentioned EP 0 446 702 B1 proposes a support means which is a surface which is movable and/or resilient within the opening—at least in part in an inclined position —at a spacing relative to the breaking-out surface and which, in its rest position, engages substantially parallel beneath the waste portion in the sheet of material and which, upon movement—that is to say primarily upon downward movement—of the waste portion, is transferred, by the breaking-out member, into an angle of inclination with respect to the sheet of material. The resilient surface can be in the form of a tongue-like spring which is fixed at one end to the breaking-out surface—substantially aligned therewith in the rest position—while the free end of the tongue-like spring is arranged in the opening. Also described are angle portions having one limb aligned with the breaking-out surface while the other limb thereof is pivotably mounted beneath the breaking-out surface and is subjected to a spring loading. The resilient surface can also be afforded by rubber profile members or by bristles.
Finally, DE-C-41 24 089 provides a cuboidal breaking-out tool of rectangular cross-section, from the pressing end of which two pressing tips or points project, in line with the two narrow sides thereof.